1. Field of the Invention
The present invention relates to a liquid transporting apparatus which transports an electroconductive liquid.
2. Description of the Related Art
A printer in which an ink-jet recording head is installed has hitherto been known as a printer which records an image and the like on a recording medium such as a recording paper. In the ink-jet recording head, a pressure is applied to the ink inside an ink channel to transport the ink to a nozzle, and further, the ink is jetted from the nozzle toward the recording medium. However, in the ink-jet recording head, a channel structure and a structure of an actuator for generating a transporting pressure and a jetting pressure for the ink is peculiar and complicated. Therefore, there have been limitations on making the recording head small when a plurality of nozzles are arranged highly densely.
In view of this, the inventor of the present invention has proposed a liquid transporting apparatus which transports an electroconductive liquid by using an electrowetting phenomenon, as an apparatus which has a simple structure than the conventional ink-jet head, and which is capable of transporting a liquid such as an ink (For example, refer to Japanese Patent Application Laid-open No. 2006-35640).
The liquid transporting apparatus described in Japanese Patent Application Laid-open No. 2006-35640 has a substrate in which a plurality of liquid channels is formed, individual electrodes (a first individual electrode and a second individual electrode) each of which is arranged half way in one of the liquid channels, and an insulating layer which covers the individual electrodes. When a driving electric potential is applied to the individual electrode, an electric potential difference between the liquid and the individual electrode is small, and a wetting angle of the liquid with respect to a surface of the insulating layer covering the individual electrode is large. Therefore, the liquid cannot move onto the surface of the insulating layer. In this case, when a driving electric potential is applied to the individual electrode, and when a predetermined potential difference is developed between the individual electrode below the insulating layer, and the liquid on the insulating layer, the wetting angle of the liquid with respect to the surface of the insulating layer becomes small (electrowetting phenomenon). Therefore, the liquid can move onto the surface of the insulating layer covering the individual electrode. According to this structure, it is possible to transport the liquid independently in the plurality of liquid channels only by changing the electric potential of the electrode (the first electrode and the second electrode), without complicating the structure of the liquid channel.